It's times like this, with grim snow, driving rain and miserable cold weather, when we batten down the hatches and hide from the world.

This is the weather where all of the maintenance measures we painfully carried out last summer pay off. The cleaning and repairing of gutters and down pipes, the re-pointing of the weathered mortar joints in brickwork and repairs to roof slates and tiles.

Unfortunately, not all of us managed to get on top of the maintenance work and some was left outstanding. In addition, the hard frosts and driving rain have caused new problems to appear.

Take the problem of the damp patch on the side wall of a terraced house in the east of Newcastle. The clients had purchased the house three years ago, and at the time the surveyor had found "rising damp on the side gable wall". The building society had made it a condition of the mortgage offer that the clients have a damp proof course fitted.

The clients engaged a reputable contractor who not only drilled the wall and injected a damp proof course, but also hacked off the old plaster and replaced it with specialist waterproof plaster.

As predicted by the contractor, the wall dried out within 10 months and all was forgotten. Until this winter.

Not long after Bonfire Night, the clients noticed a brown stain just above the line of the replaced plaster. Within a couple of weeks the stain became more pronounced. Their first thought was the damp proof course had failed. Out came the contractor, carried numerous tests and pronounced that the course was working fine.

So what was the cause? Many years ago, a previous owner, in an attempt to rectify the rising damp on the inside of the wall, had applied a coat of render to the outside of the wall, up to about 1.2m (4ft) above ground level. The render was discoloured and looking sad when the clients bought the house, so they painted the render with a smart cream paint that also sealed it against penetrating dampness.

Above the rendered panel was the original brickwork. As the brickwork is almost 100-years-old, the mortar joints are getting a bit tired and washed out. Under normal circumstances we could have said that it would need to be re-pointed in five-10 years. However, that was discounting the effect of the painted and sealed render, coupled with the new plasterwork internally.

Our conclusion was that the dampness appearing on the inside of the wall, about 0.9m (3ft) above the floor level, is being caused by rain water soaking through the outside of the wall above the rendered area. The poor brickwork pointing is not shedding the water clear of the wall but allowing it to soak back into the bricks. The water then trickles through the wall.

Under normal circumstances, the water would drain down to the bottom and out above the damp proof course. Here, however, the render is trapping it into the wall and the new paint finish is stopping it from draining away.

On the inside of the wall, the water cannot soak out at low level because of the new plaster, so it builds up until it appears in the original plaster, above the line of the new plaster. The lower wall is now pretty much saturated.

The solution is to remove the render and repoint the brickwork. Removing the render will leave an unsightly pattern on the wall, so it will need to be painted, but this time using a porous paint to let the wall dry out.

In some ways it was a relief to the clients that it wasn't the damp proof course, but it still means more tasks are added to the never ending list of maintenance jobs.